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U Frucht

Publications and source records attributed to U Frucht.

15 recordsLinked to original sources
PubMed1993

[The reliability of the measurement of non-invasive oscillometric blood pressure instruments].

METHODS: The performance of five oscillometric blood pressure monitors was tested by means of a simulator. The oscillometric signals of two healthy patients were replayed. These signals were superimposed by sinusoidal artefacts with increasing amplitude, to examine the influence of artefacts on the accuracy of the measurement. Each measurement was repeated 15 times. RESULTS: The artefacts taken for this examination did affect the scattering of each single measurement rather than the mean value of the repeated measurements. The results did get worse with decreasing signal-to-artefact ratio. However, some monitors are able to handle these artefacts better than others. CONCLUSION: It is obvious that the implemented software for the artefact treatment and the determination of blood pressure values differs from manufacturer to manufacturer. Some devices were able to separate relevant signals from artefacts better than others. The most critical point of the oscillometric method is the correct determination of the maximum amplitude of the oscillations, because it directly influences the accuracy of the displayed blood pressure values. The availability of a simulator to test automated sphygmomanometers has shown to be a good tool to examine the performance of these devices.

Artifacts↗
PubMed1989

[Comparative study of unidirectional transducers for invasive blood pressure monitoring].

This paper reports on the results of a study in which the offset drift, sensitivity error and drift, as well as the linearity error of six DPT's were investigated under normal ambient conditions and varying conditions of temperature, light, operating time and variation of supply voltage. In addition, the dynamic response, and the influence of storage at extreme temperatures, and resterilisation, was examined. The electrical and mechanical safety/reliability of DPT's was also investigated. The results obtained are compared.

Blood Pressure Determination↗
PubMed1987

In vitro clonality of carcinomas as a prognostic parameter for the survival time of patients.

Clonal growth of tumour cell explants of squamous cell carcinomas of the jaw and face area can be induced in vitro. According to the clonality of tumours, the following 2 patient groups can be clearly distinguished: Patients with carcinomas whose in vitro growth involves a small number of clones (less than 45/1 X 10(5) cells disseminated). Patients with carcinomas whose in vitro growth involves a large number of clones (more than 45/1 X 10(5) cells disseminated). Demonstrating the same prognostic factors, these two patient groups have a significantly different life expectancy (p = 0.0001) 24 months following establishment of the diagnosis and cloning: more than 70% of the patients with low-cloning carcinomas, and less than 30% of the patients with high-cloning carcinomas are still alive. In vitro clonality of tumours is thus a prognostically relevant indicator of the expected survival time of affected patients.

Adult↗
PubMed1987

[Content of trace elements in solutions for parenteral nutrition and blood derivatives].

Intravenous solutions contain both essential and nonessential trace elements. The manufacturer is not obliged to declare the concentration of trace elements contained therein. Therefore, a study was done to investigate the concentration of magnesium, copper, chromium, manganese and cobalt, as well as a possible contamination by aluminum and nickel, in 15 solutions used for parenteral nutrition and blood products applied in Germany. Measured against the daily parenteral requirements, negligible concentrations were found for all essential trace elements with the exception of chromium and cobalt. A marked contamination by the nonessential metal ions aluminum and nickel was detected in the 5% protein- and 20% albumin-solutions. Aluminum concentration was 16-49 mumol/l in the blood products and up to 4.9 mumol/l in the nutrient solutions. The concentration of nickel found in the protein- and hydroxyethyl starch solutions was 250 times higher than the normal serum level. It must be assumed that different manufacturing procedures lead to the different degrees of contamination of the solutions (up to 100%). In view of more recent publications, the aluminum contamination may be a potential hazard to patients with prolonged parenteral nutrition and certain risk groups among the critically ill.

Blood Transfusion↗
PubMed1987

[Patient-adapted, ion selective analysis--characteristics of a new instrument].

We report on a newly developed instrument with ion-selective electrodes (IONOMETER EF) for the measurement of sodium, potassium and calcium. The measurements in whole blood and plasma from intensive care patients were compared with flame photometry. We assessed the precision and accuracy of these measurements. The precision of the analysis is excellent: K+ 4.69 +/- 0.03 mmol/l; Na+ 139.2 +/- 0.27 mmol/l; Ca++: 1.23 +/- 0.03 mmol/l. When assessing the accuracy, the characteristics of the ionselective device have to be considered, as well as differences in solvent volumes, when compared with flame photometry. The correlation coefficient of potentiometric analyses of whole blood and plasma is r = 0.99. It seems to be appropriate to define new normal ranges for ionselective electrode systems.

Blood Chemical Analysis↗
PubMed1986

[Computer-assisted regulation of blood pressure by drugs acting on the cardiovascular system. Problems in the development of a closed-loop control system].

This article reports on the problems associated with the development and use of a computer programme for computer-monitored blood pressure control by means of cardio- and/or vasoactive drugs. The computer, a monitoring device routinely used in hospitals, and an infusion pump on the one hand, and the patient on the other, are part of a closed loop control system. Regulation is effected in the manner practised in hospitals, the mean arterial pressure (MAP) serving as an auxiliary controlled variable. The computer programme analyses the directly measured blood pressure curve in two respects: Detection and assessment of external disturbing factors and endogenously conditioned changes in the blood pressure curve and determination of MAP via a special control algorithm. With the help of a prototype of the automatic controller, the programme was subjected to extensive clinical trials in more than 140 patients to date. The programme was particularly successful wherever a residual circadian rhythm leads to variable requirements of vasopressor or cardiovascular drugs. The use of technical control algorithms has proved unsuitable because of the complex nature of blood pressure control.

Algorithms↗
PubMed1985

[Toxic methemoglobinemia following the postoperative ingestion of 4,4-diaminodiphenylsulfone (DADPS)--on the differential diagnosis of cyanosis].

Blood gas analysis devices routinely used in clinical practice measure pH, pCO2 and pO2 directly, while all other values they specify are calculated on the basis of nomograms. In the presence of higher concentrations of biologically useless forms of haemoglobin, calculation of the haemoglobin saturation (% O2 Hb) leads to a clinically relevant false assessment of oxygen availability. A case is described in which toxic methemoglobinaemia occurred postoperatively after resumption of long-term medication with 150 mg 4,4-diaminodiphenylsulfone (DADPS). Increasing methaemoglobin values up to maximal 17.7% at a total haemoglobin of 11.3 g/dl correlated with the symptoms of cyanosis and respiratory distress. This symptom complex, which is not atypical postoperatively, could not be clarified by differential diagnosis with the aid of cardiac output measurements and arterial blood gas analyses. The cardiac index amounted to 4.1 l/m2 at a pulmonary capillary wedge pressure of 8 mmHg; the arterial partial oxygen pressure was between 16 and 19 kPa. Only the differential determination of oxihaemoglobin, CO-haemoglobin and methaemoglobin with an oximeter yielded evidence of severe arterial hypoxaemia and made therapy possible.

Adult↗
PubMed1984

[Respiratory controlled intermittent inspiratory pleural drainage--a method for handling life threatening bronchopleural fistulas].

A report is presented on a technical device for artificial ventilation of patients with severe bronchopleural fistulae. The respirator-controlled apparatus interrupts drainage suction at the beginning of inspiration and releases it again at expiration. In contrast to similar constructions, this system does not allow drainage secretions to influence its functional efficiency. Modifications for connection of this apparatus are conceivable for all modern respirators. A case is described in order to demonstrate the effectiveness of the procedure. The hitherto published literature is critically reviewed.

Adult↗